@article{Garrel2020WittAC,
title={Witt and cohomological invariants of Witt classes},
author={Nicolas Garrel},
journal={Annals of K-Theory},
year={2020}
}

We classify all Witt invariants of the functor $I^n$ (powers of the fundamental ideal of the Witt ring), that is functions $I^n(K)\rightarrow W(K)$ compatible with field extensions, and all mod 2 cohomological invariants, that is functions $I^n(K)\rightarrow H^*(K,\mu_2)$. This is done in both cases in terms of certain operations (denoted $\pi_n^{d}$ and $u_{nd}^{(n)}$ respectively) looking like divided powers, which are shown to be independent and generate all invariants. This can be seen as a… Expand

This volume concerns invariants of G-torsors with values in mod p Galois cohomology - in the sense of Serre's lectures in the book Cohomological invariants in Galois cohomology - for various simple… Expand

Cohomological invariants, Witt invariants, and trace forms: Contents by J.-P. Serre and S. Garibaldi Introduction by J.-P. Serre and S. Garibaldi The notion of "invariant" by J.-P. Serre and S.… Expand

Let k be a field with char k 6= 2. For i = 6, 7 we define invariants hi : H ( k,Spin(14) ) → Hi(k,Z/2)/(−1)Hi−1(k,Z/2). Further we show that the natural map H ( k, (G2 ×G2) o μ8 ) → H ( k,Spin(14) )… Expand

Introduction Classical theory of symmetric bilinear forms and quadratic forms: Bilinear forms Quadratic forms Forms over rational function fields Function fields of quadrics Bilinear and quadratic… Expand

We study the degree 3 cohomological invariants with coefficients in Q/Z(2) of a semisimple group over an arbitrary field. A list of all invariants of adjoint groups of inner type is given.

We introduce series of invariants related to the dimension for quadratic forms over a field, study relationships between them and prove a few results about them.